1. Field of the Invention
The present invention relates to an anti-snoring device.
2. Description of the Related Art
This application discloses an anti-snoring device of the types generally described in my prior U.S. Pat. No. 5,921,241, issued Jul. 13, 1999; U.S. Pat. No. 5,810,013, issued Sep. 22,1998 and U.S. Pat. No. 5,720,302, issued Feb. 24, 1998.
As disclosed in my aforementioned patents (the disclosures of which are incorporated by reference herein), snoring or sleep apnea is caused by the condition where the tongue relaxes and contributed to blocking off the air passageway in the pharynx or lingual compartment. The soft tissue within the mouth cavity including the tongue, the pharyngeal folds, the soft palate, the muscalaris uvulae and the palate-pharyngeal arch tend to vibrate as tidal air flows past during sleep which also causes snoring.
When the tongue musculature relaxes during sleep, gravity causes the tongue to drift inferiorly and posteriorly, thereby impacting or occluding against the surrounding structures of the airway, including the uvulvae and soft palate. When the airway is thus occluded, the patient gasps for air, a condition known as obstructive sleep apnea.
Anti-snoring devices are effective when they protract (pull or hold) the mandible (lower jaw) forward and upward and elevate the tongue, superiorly and anteriorly, so that the tongue does not occlude the air passageway by drifting inferiorly and posteriorly while sleeping. Most anti-snoring devices accomplish this task by holding the lower jaw forward against a rigid dental overlay component, which is fixed to the upper teeth, or to the upper and lower teeth. These anti-snoring devices fix the dental overlay component from falling out of the mouth by clasping or biting of the user's teeth into the dental overlay component and by close adaptation to the user's teeth.
There are two general classes of these oral appliances. One group, known as custom appliances, are formed as rigid plastic structures that are made by dental laboratories upon molds of a patient's teeth. Custom appliances are made of methacrylate resins. The other group, known as boil and bite appliances, is made from moldable thermolabile elastomeric materials such as ethylene vinyl acetate, and may also employ a hard plastic substructure. These devices need no dental impressions or lab procedures and are custom fitted directly upon the patient.
Boil and bite devices are first softened in near boiling water for between several seconds and one minute. The softened device is then placed on the upper or lower teeth. The patient is instructed to bite into the softened material to make an impression of the teeth in the softened material, allow the material to cool while it molds to the teeth. In some cases, excess material is then trimmed away. The appliance is then tested for comfort and fit.
Both classes of devices advance the lower jaw and the tongue (which is attached to the lower jaw) so that the tongue does not occlude the airway and normal respiration can take place. However, the devices differ in their ability to allow the lower jaw freedom of lateral motion.
The freedom to move the lower jaw laterally while it is held in its advanced posture is necessary to prevent soreness in the temporomandibular joints (TMJ) and the surrounding facial musculature. When the mandible is restricted from moving all night long the temporomandibular joints become stiff and the masticatory muscles and joints become temporarily dysfunctional. This results in the patient's non-compliance with the therapy.
Some of the rigid plastic anti-snoring devices (the custom appliances) permit lateral motion of the lower jaw. Such devices incorporate swivels or hinge mechanisms to join opposing upper and lower plates. In the boil and bite appliances, such hinges or swivels have been difficult to incorporate. In addition, such hinges and swivels require use of substantial interocclusal space. Interocclusal space is the vertical spacing between the opposing jaws when the jaws are in their normal resting posture (rather than closed together). If unduly thick or bulky anti-snoring appliances impinge upon this space, it is uncomfortable for the patient, it is more difficult to achieve required mandibular advancement, and the efficacy and patient compliance are decreased.
The prior art boil and bite appliances that permit lateral movement of the lower jaw while it is postured in the advanced position are disclosed in my aforementioned patents and in Halstrom U.S. Pat. No. 5,868,138. The Halstrom "boil and bite" appliance is a double plate structure joined by a swivel stem and hole assembly, which adjustably couples the upper and lower plates. It is bulky and thus it is difficult for the patient to close the lips over the appliance when it is placed in the mouth. The patient must open the mouth very wide to bite into the softened material. A clinician's assistance is required to properly place the appliance between the jaws and to properly align the teeth within the appliance. Patients cannot do this themselves with assured accuracy; thus, misalignment reduces the efficacy and adjustabililty of the appliance.
Double plate appliances require more space than signal plate appliances to accommodate the mechanical swivel, to provide sufficient space between the upper and lower plates to allow the patient sufficient tongue space, and to provide air holes for breathing.
The appliances disclosed in my aforementioned patents are single plate structures having no upper plate. They provide freedom of lateral motion, adequate tongue space, and sufficient space for passage of air during breathing.
Other boil and bite appliances of the prior art are single component structures, which utilize an upper dental plate and have a lower guide ramp, which engages the lower jaw just behind the lower teeth. The guide ramp in these devices is fixed to the upper dental plate so that the mandible is rigidly or nearly rigidly held in the anterior advancement. These appliances require skilled manipulation by a dentist. For example, the appliance disclosed in Shapiro, et al U.S. Pat. No. 5,117,816 uses a special handle to place the softened appliance properly and guide the mandible into its forward posture. Often, locating the correct jaw advancement to achieve reduction of obstructive sleep apnea is difficult. Often, the mandible is incorrectly advanced so that the patient closes down into the softened device incorrectly resulting in TMJ pain and decreased efficacy of the appliance.
The re-fitting process to locate correct jaw advancement requires that the appliance be re-softened and re-inserted in the mouth to imprint a more forward jaw posture into the material.
Another appliance disclosed in U.S. Pat. No. 5,092,346 to Hays and Meade manually places the appliance but requires periodic trimming and remolding of the ramp by softening the appliance in hot water to effect sequential mandibular advancement.
The prior art boil and bite guide ramp appliances do not provide sufficient lateral motion. Many of the prior art custom appliances that provide the required amount of lateral motion are either too costly, or too difficult for the non-dentist technologist to fit.